<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #boll{
            width: 100px;
            height: 100px;
            background-color: red;
            border-radius:50%;
            margin-left: 100px;
        }
    </style>
    <script src="../myCommon.js"></script>
</head>
<body>
<div id="boll"></div>
<input type="button" value="移动小球" onclick="mov()">
    <script>
        var boll=$("boll");
        var z = window.getComputedStyle(boll).marginLeft
        console.log(z)
    </script>

</body>
</html>